Protective Cap

ABSTRACT

A protective cap for cylindrically mounted optical elements includes a retaining ring which is placed on a cylinder ring so as to be rotatable. The retaining ring covers the circumferential surface of the cylinder ring in a form-fitting manner. A latching mechanism having a latching element which engages in the latching mechanism in a force-fitting or form-fitting manner is present between the cylinder ring and retaining ring. The latching element is releaseable by an actuating element which is mounted on the retaining ring. A folding hinge for fastening and moving a protective cover from a covering position into a spatially fixed open position is present on the retaining ring.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119 from GermanPatent Application No. 10 2017 104 083.8, filed Feb. 27, 2017, theentire disclosure of which is herein expressly incorporated byreference.

BACKGROUND

The embodiments of the invention relate to a protective cap forcylindrically mounted optical elements, in particular eyepieces orobjectives on telescopes.

Objective mountings may be provided on the front side with an internalthread into which filters or diaphragms provided with an external threadcan be screwed. DE 10 2006 036 890 B4 discloses cylinder rings whichallow accessory parts to be received such that they are oriented in arotationally secure manner.

Protective caps for objectives may also have a wide variety of designs.The protective caps are either pushed directly onto an objective tube orheld on a retaining ring pushed onto the objective tube.

DE 20 2015 102 076 U1 discloses a retaining ring which has retainingeyes which are mounted in an oriented manner and into which a protectivecover can be inserted by means of a flexible lug. The orientation of theretaining eye is for example such that, after being released from theobjective, the protective cover hangs freely downward on the retainingring and does not hinder the view through the objective. The protectivecover can be securely inserted in a positionally fixed manner and forprotection against environmental influences into the objective mountingby means of an annular bead which is placed under radial tension by anannular spring.

The protective covers are usually produced from a flexible plastic orrubber.

For use on telescopes, in particular on telescopic sights mounted on aweapon, a downwardly hanging protective cover is obstructive because,given that it rests movably on the weapon, it can hinder the viewthrough the objective or limits the distance between the eyepiece andthe eye of the user.

In the case of telescopic sights on hunting weapons, protective coversmade of plastic or rubber entail the risk that, when the weapons arebeing carried in hunting grounds, said covers can be damaged orpenetrated by branches, with the result that the front lens of thetelescope objective can be damaged.

SUMMARY

The inventive protective cover mounted on a retaining ring may befastened in such a way that, after being released from its protectivefunction, it can be brought into radially different, stable, inparticular impact-secured, rest positions. In addition, the protectivecover offers secure protection against penetration.

The protective cap comprises two ring elements of which the outer coversthe inner in a form-fitting manner and is rotatable thereon. For use ofthe protective cap, the inner cylinder ring is screwed into thefront-side opening of the cylindrical mounting of an optical element.The outer ring element is provided as a retaining ring with a foldinghinge for fastening and moving the protective cover from a position forcovering the optical element into an open position.

In order to be able to firmly screw the protective cap into acylindrical mounting of an optical element, a latching mechanism ispresent between the outer retaining ring and the inner cylinder ring.Releasing this latching mechanism allows the retaining ring to bebrought into an orientation with respect to the cylinder ring in whichthe folding hinge bearing the protective cap holds the protective cap inthe open position in the desired rest position.

In order to screw the cylinder ring into the cylindrical mounting of anoptical element, the cylinder ring is provided with an external threadwhich, when firmly seated in the cylindrical mounting, must not hinderthe rotatability of the retaining ring. This may be achieved by limitingthe screwing-in depth through adaptation between the length of theexternal thread and the thread depth on the cylindrical mounting.

To compensate for tolerances between the two stated dimensions, theexternal thread may be provided in the root region with an undercut intowhich there may be inserted an O ring as a squeezing element which, onthe one hand, allows a firm seating in the screw-in thread and, on theother hand, limits the space between the edge of the cylindricalmounting and the retaining ring only to the extent that the rotatabilityof the latter is not hindered.

The latching mechanism between the cylinder ring and the retaining ringcomprises toothing mounted on the outer circumference of the cylinderring and a latching element which, as a latching block, is formed withtooth elements which engage in the toothing in a force-fitting orform-fitting manner.

The toothing preferably takes the form of rectangular toothing whichallows a form-fitting engagement of the likewise rectangular latchingelements of the latching block in the toothing on the cylinder ring,thereby ensuring a play-free rotation of the protective cap uponscrewing into the cylindrical mounting of the optical element to beprotected.

The latching mechanism may be released manually. For this purpose, anactuating element is preferably present on the folding hinge. Theactuating element can comprise a plunger which is displaceabletangentially to the retaining ring counter to a spring pretensioning,and thereby lifts the tooth elements of the latching block out of thetoothing on the cylinder ring. Upon release of the actuating element,the tooth elements of the latching block automatically spring into thetoothing on the cylinder ring and secure the selected rotary position ofthe retaining ring. Alternatively, instead of the plunger arrangement, atilting lever for lifting the latching block may also be present.

The protective cover is pivotable about a pivot pin on the foldinghinge. This pivot pin may be fastened to the folding hinge in the frontregion of the attached protective cap, i.e. above the front side of thecylinder ring and retaining ring or somewhat set back, i.e. in thedirection above the external thread. The somewhat set back arrangementwith respect to the front side allows a more pleasing design of theoverall arrangement and, owing to the angular position of the pivot pinwith respect to the covering position, this set back arrangement alsoallows for better securing against unintentional folding-away of theprotective cover.

When rotating the protective cover about the pivot pin, the latter mayinteract with a tensionable leg spring. Upon closing the opticalelements, said leg spring supports the covering position of theprotective cover. On the other hand, a certain degree of friction may bepresent in the mounting of the pivot pin, this friction counteracts thetension of the leg spring and allows the protective cover to rest in anydesired pivoted position.

Particularly, when using the protective cap for protecting the opticalfront elements of telescopic sights and the eye of the person takingaim, the position of the pivoted-out protective cover also remainsunchanged upon recoil on a weapon. For this purpose, there may bearranged at least one magnet on the folding hinge and/or a magnet on theprotective cover such that they secure the pivoted position throughtheir magnetic force. A pivoted position is preferably chosen in whichthe protective cover in the open position lies parallel to the opticalaxis of the optical element to be protected.

A secure covering position of the protective cover may also be provided.For this purpose, a further ring element may be inserted on the frontside into the cylinder ring or the retaining ring, which ring elementmay consist either of a deformable plastic, rubber, or of metal. Here,the further ring element is intended to project with respect to thecylinder ring and/or retaining ring, and to have a deformable bead onits exposed outer circumference. Said bead can be formed either by theplastic of the further ring or by an inserted O ring.

Here, the protective cover is expediently formed with a pot-shaped edgein the interior of which a groove adapted to the bead is incorporated.The groove depth may be designed to decrease starting from the foldinghinge, the depth being less than the bead height at the shallowestpoint. During engagement between the groove and bead, the pot-shapededge of the protective cover is braced with respect to its pivot pin,and thus securely held in the covering position. Further, one or moreclips which engage around the retaining ring can be integrally formed onthe pot-shaped edge of the protective cover.

Exemplary embodiments of the inventive protective cap are schematicallyillustrated in the drawings and are described in more detail below withreference to the figures, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross section through the protective cap with set-backpivot pin,

FIG. 2 shows a cross section with front-side pivot pin,

FIG. 3 shows a cross section with latching mechanism,

FIG. 4 shows a perspective view of the latching mechanism,

FIG. 5 shows a lifting device for actuating the latching mechanism,

FIG. 6 shows the arrangement of a magnet in the folding hinge and cover,

FIG. 7 shows the arrangement of two magnets in the folding hinge,

FIG. 8 shows a cross section with additional ring element on theretaining ring, and

FIG. 9 shows a protective cover with clips for engaging around theretaining ring.

DETAILED DESCRIPTION OF EMBODIMENTS

The protective cap 1 illustrated in FIG. 1 comprises an inner cylinderring 2 and a retaining ring 3 rotatably mounted thereon. A folding hinge4 is fastened to the retaining ring 3.

The cylinder ring 2 comprises an external thread 5 for screwing into acylindrical mounting (not shown) of an optical element to be protected.The length of the external thread 5 is chosen such that, in interactionwith the screw-in thread of the mounting of the optical element, it doesnot hinder the rotatability of the retaining ring 3.

The folding hinge 4 comprises a pivot pin 6 which may be set back withrespect to the front side of the protective cap 1 with the protectivecover 7 in the direction of the external thread 5. The pivot pin 6interacts with a tensionable leg spring 8 (not shown further).

The bent-off lever region 9 which extends from the pivot pin 6 to theprotective cover 7 results, on the one hand, in a stable position of theprotective cover 7 in the covering position illustrated and, on theother hand, in a more pleasing appearance of the overall arrangement.

Arranged within the folding hinge 4 is a latching mechanism whichcomprises toothing 10 present on the outer circumference of the cylinderring 2 and a latching block 11 with tooth elements 12. The engagement ofthe tooth elements 12 in the toothing 10 may be released by manualactuation of a plunger 13 in order to bring the retaining ring 3 into adesired rotary position with respect to the cylinder ring 2.

A ring element 14 is screwed into the cylinder ring 2 on the front side.The ring element 14 projects with respect to the front-side end of thecylinder ring 2 and comprises an external circumferential bead 15 inthis edge region. The protective cover 7 is provided with a pot-shapededge 16 in the interior of which a groove 17 is incorporated. In theupper region pointing toward the pivot pin 6, this groove 17 has agreater depth than diametrally opposite in the lower region, the groovedepth at the shallowest point being less than the bead height on thering element. In the state in which it covers the optical element to beprotected, the protective cover 7 is therefore clamped in the lowerregion between the bead 15 and groove 17, with the result that thecovering position is secured against unintentional opening. The clampedstate may be achieved by powerful folding down of the protective cover 7or by manual pressure.

FIG. 2 shows a pivot pin 6 on the folding hinge 4 that is orientedsubstantially aligned with the direction of the protective cover 7 inthe covering state. The region of an undercut 18 on the external thread5 is filled with an O ring 19 here. When screwing into the cylindricalmounting of an optical element to be protected, said mounting cuts intothe O ring 19 or squeezes it against an end region of the retaining ring3 without adversely affecting the rotatability thereof. The arrangementconsisting of the cylinder ring 2 and retaining ring 3 can also besecured against falling apart by the insertion of the O ring 19.

The inner cylinder surface of the cylinder ring 2 and of the ringelement 14 are configured so as to be slightly conical toward theoutside in order to not constrict the opening angle of the bundle ofrays to be received by the optical system to be protected.

FIG. 3 shows in cross section the rectangular toothing 10 a on the outercircumference of the cylinder ring 2. The tooth elements 12 a on alatching block 11, which are adapted to the toothing 10 a engage in thistoothing, and thus fix the relative position between the folding hinge 4and cylinder ring 2.

The plunger 13 is mounted in the folding hinge 4, so as to bedisplaceable tangentially to the cylinder ring 2 counter to the pressureof a spring 20. Via a pin 21 which is guided in an oblique slot (notshown here), the plunger 13, when pressed in manually, raises thelatching block 11 and lifts the tooth elements 12 a out of therectangular toothing 10 a.

Lugs 27 which can be used for manually lifting and pressing theprotective cover 7 are integrally formed on the protective cover 7.

FIG. 4 shows in further detail the function of the plunger mechanismwith the oblique slot 22 in which the pin 21 on the plunger 13 isguided.

FIG. 5 shows a lifting device 26 with latching block 11.

FIG. 6 shows the arrangement of a magnet 23, 24 both in the foldinghinge 4 and in the protective cover 7, which attract one another bymagnetic force in the folded-open state of the protective cover 7.

FIG. 7 shows the same arrangement, in which in the folding hinge 4 thereis a further magnet 25 which interacts with the magnet 24 in theprotective cover 7 in the covering position. In the open position, theprotective cover 7 is oriented parallel to the optical axis of theoptical system to be protected.

FIG. 8 shows the ring element 14 being screwed into the retaining ring3. With this configuration, the rotatability of the retaining ring 3 onthe cylinder ring 2 may not hindered by the ring element 14. Inaddition, the retaining ring 3 pushed over the external thread 5 and thetoothing 10 are secured by the insertion of an O ring 19 into theundercut 18 against falling apart prior to screwing into the cylindricalmounting of an optical element.

FIG. 9 shows the arrangement of a clip 28 on the pot-shaped edge 16 ofthe protective cover 7 as an additional securing means for the coveringstate of the protective cover 7 on the retaining ring 3.

LIST OF REFERENCE SIGNS

1 Protective cap

2 Cylinder ring

3 Retaining ring

4 Folding hinge

5 External thread

6 Pivot pin on the folding hinge

7 Protective cover

8 Leg spring

9 Pivot pin/protective cover lever

10 Toothing on cylinder ring

10 a Rectangular toothing

11 Latching block

12 Tooth elements

12 a Rectangular tooth elements

13 Plunger

14 Ring element

15 Bead on ring element

16 Pot-shaped edge

17 Groove in the pot-shaped edge

18 External thread undercut

19 O ring on the external thread

20 Compression spring on the plunger

21 Pin on the plunger

22 Slot in the latching block

23,25 Magnet on the folding hinge

24 Magnet on the protective cover

26 Lifting device

27 Lug on the protective cover

28 Clip on the protective cover

The foregoing disclosure has been set forth merely to illustrate theembodiments of the invention and is not intended to be limiting. Sincemodifications of the disclosed embodiments incorporating the spirit andsubstance of the invention may occur to persons skilled in the art, theembodiments of the invention should be construed to include everythingwithin the scope of the appended claims and equivalents thereof.

What is claimed is:
 1. A protective cap for cylindrically mountedoptical elements, comprising: a retaining ring which is placed on acylinder ring so as to be rotatable, wherein the retaining ring coversthe circumferential surface of the cylinder ring in a form-fittingmanner, a latching mechanism having a latching element which engages inthe latching mechanism in a force-fitting or form-fitting manner ispresent between the cylinder ring and retaining ring, the latchingelement is releaseable by an actuating element which is mounted on theretaining ring, and a folding hinge for fastening and moving aprotective cover from a covering position into a spatially fixed openposition is present on the retaining ring.
 2. The protective cap asclaimed in claim 1, wherein the cylinder ring has an external thread forscrewing into the cylindrical mounting of the optical elements.
 3. Theprotective cap as claimed in claim 2, wherein the length of the externalthread is adapted to the screwing-in depth in the cylindrical mounting.4. The protective cap as claimed in claim 3, wherein the external threadhas in the root region an undercut for inserting an O ring which doesnot hinder the rotatability of the retaining ring.
 5. The protective capas claimed in claim 1, wherein the latching mechanism comprises atoothing mounted on the outer circumference of the cylinder ring and alatching element which, as a latching block, is formed with toothelements which engage in a force-fitting or form-fitting manner in thegaps of the toothing.
 6. The protective cap as claimed in claim 5,wherein the toothing and the tooth elements are rectangular toothing. 7.The protective cap as claimed in claim 1, wherein the latching elementis manually actuatable.
 8. The protective cap as claimed in claim 1,wherein the latching block and its actuating element are arranged on thefolding hinge.
 9. The protective cap as claimed in claim 8, wherein thelatching block liftable out of the toothing in the radial direction tothe cylinder ring by a plunger which is displaceable tangentially to thecylinder ring counter to a compression spring.
 10. The protective cap asclaimed in claim 9, wherein the latching block is actuatable via alifting device which is under spring pretensioning.
 11. The protectivecap as claimed in claim 1, wherein the folding hinge has a pivot pinwhich is arranged above the front side of the retaining ring.
 12. Theprotective cap as claimed in claim 2, wherein the folding hinge has apivot pin which is arranged above the end of the retaining ring thatpoints toward the external thread.
 13. The protective cap as claimed inclaim 12, wherein the pivot pin interacts with a leg spring which istensionable during the rotation of the folding hinge.
 14. The protectivecap as claimed in claim 1, wherein the folding hinge comprises at leastone magnet which interacts with a magnet arranged in the protectivecover so that at least one discrete folding position of the protectivecover is maintainable in an impact-secured manner.
 15. The protectivecap as claimed in claim 1, wherein a ring element is screwed into thefront-side opening of the cylinder ring, which ring element consists ofdeformable plastic and has an edge, which projects with respect to thecylinder ring, with an outwardly pointing circumferential bead, orconsists of metal, an O ring as a deformable bead being inserted intothe edge.
 16. The protective cap as claimed in claim 1, wherein a ringelement is screwed into the front-side opening of the retaining ring,which ring element consists of deformable plastic and has an edge, whichprojects with respect to the retaining ring, with an outwardly pointingcircumferential bead, or consists of metal, an O ring as a deformablebead being inserted into the edge.
 17. The protective cap as claimed inclaim 15, wherein the protective cover is formed with a pot-shaped edgewhich engages over the ring element and in the interior of which agroove adapted to the bead is incorporated.
 18. The protective cap asclaimed in claim 17, wherein the groove depth is designed to decreasefrom the region of the folding hinge to a diametrally opposite region.19. The protective cap as claimed in claim 18, wherein the groove depthat the shallowest point is less than the bead height on the ringelement.
 20. The protective cap as claimed in claim 17, wherein at leastone clip which engages over the retaining ring is attached to thepot-shaped edge of the protective cover.
 21. The protective cap asclaimed in claim 16, wherein the protective cover is formed with apot-shaped edge which engages over the ring element and in the interiorof which a groove adapted to the bead is incorporated.
 22. Theprotective cap as claimed in claim 21, wherein the groove depth isdesigned to decrease from the region of the folding hinge to adiametrally opposite region.
 23. The protective cap as claimed in claim22, wherein the groove depth at the shallowest point is less than thebead height on the ring element.
 24. The protective cap as claimed inclaim 21, wherein at least one clip which engages over the retainingring is attached to the pot-shaped edge of the protective cover.